*your alleles increase in the next generation with the increased fitness to you OR your family

The r term indicates the degree of relatedness (a child is r=.5, a sibling is r=.25)

Parental care is simplest case of a trait evolving by kin selection. If altruistic trait A is to continue a mother will only sacrifice herself if 3 children are saved (rb >c = (.5)(3)>1)

Indiscriminate altruism cannot evolve by NS, because only

Under what circumstances would parental care evolve? Consider this in terms of Hamilton's equation.

The benefit would have to be greater than (not equal to) the cost.

If altruistic trait A is to continue a mother will only sacrifice herself if 3 children are saved (rb >c = (.5)(3)>1)

Expand your consideration to include 2nd degree relatives such as nieces/nephews. Under what circumstances would kin selection for these relatives be favored?

The relatedness factor for a 2nd degree relative would be much lower than a direct offspring (.25 vs .5)

In this case it would require more than 4 nieces saved (not equal to 4) to equal the cost of a death (fitness -1)

What is an ESS? How does a fiddler crab claw display behavior fit the requirements of an ESS?

ESS = Evolutionary Stable Strategies

A strategy such that, if all the members of a population adapt it then NO mutant strategy could invade under the influence of NS

The claw is used to fight males and attract females

A regenerated claw is an effective bluff, although it is actually much weaker than the original claw

Cooperation among unrelated individuals is, on the surface, altruistic. How does the example of the cuckoo contradict this surface assessment? How does the example of the pied kingfisher contradict this surface assessment? How does the example of the vampire bat contradict this surface assessment? In all of these cases, why is the cooperation not really altruistic?

Cuckoo: Manipulation- a brood parasite who manipulates its host into providing aid to its young

Kingfisher: Individual advantage- helps non-relatives rear children to make themselves more attractive

Vampire bat: Reciprocation- feed regurgitated blood to roost members if no others were successful, this will be reciprocated in the future

The cost is not larger than the benefit to the host

How is eusociality the most extreme case of kin selection? What species of mammal is eusocial? What insects are eusocial?

Sterile workers rear the kids of their mom

The only eusocial mammal is the naked mole rat

Termites and many hymenoptera

How does a haplodiploid genetic system in the social Hymenoptera pre-dispose these species for eusociality? What evidence exists to support the hypothesis that haplodiploidy is the driving force behind eusociality in these insects?

females are from fertilized eggs (diploid)

males are from unfertilized eggs (haploid)

In diploids r=.5 btwn parent/offspr and ~.5 btwn siblings

Queens typically mate with a single male, so that all females inherit the males chromosome

Thus a female is more closely related to her sisters (.75) than her daughters (.5) or her brothers (.25)

Queen's fitness is maximized by equal investment in daughters and sons, because r=.5 to both, but fitness of workers is maximized if 3/4 of siblings are sisters and 1/4 are brothers

In colonies with >1 queen sex ratios ~1:1 because workers may not be full sisters

How is infanticide by males who are not the father of the infant (as in lions or langurs) an example of a genetic conflict between males and females? How do females make the best of a bad deal in such conflicts?

Infanticidal males cause females to go into heat faster and thus can father their own children faster

Under what circumstances would infanticide by parents be selectively favored? Provide an explicit example

Parents can kill/abort offspring as a way to adaptively regulate brood size or sex ratio

Great tit populations in Oxford, England show that a clutch size of >8.5 eggs results in too much competition, and the rate of survival decreases

Easier to kill than neglect and cause issues amongst entire brood

Under what circumstances would siblicide by siblings be selectively favored? Provide an explicit example.

In some eagle and boobie species, larger kids in broods may kill smaller siblings

Brown booby: survivors of sibling competition depends on food supply

Shark siblings eat eachother in the uterus

How can genetic conflict exist at the level of individual genes? Provide an explicit example.

A gene that adjusts the sex ratio of kids toward females would be in conflict with a gene that adjusts the ratio toward neutral or males

Consider endosymbiotic parasites. Their genome is in direct conflict with the genome of the host. Under what circumstances would extreme conflict (ie. using all the host's resources and killing the host quickly) be favored? Under what circumstances would reduced conflict (ie. reduced virulence) be favored?

If endosymbionts are passed horizontally within a host population than NS favors genotypes with high reproduction rate, even if the host dies

If endoysmbionts are passed vertically from parent to offspring then the RS of the symbiont depends on host fitness

Consider an endosymbiotic mutualist, such as the ancestral mitochondria which was engulfed by the ancestral eukaryote. Why did this cooperative relationship evolve? What must be the foundation of all mutualistic or symbiotic relationships? (think b>c)

This relationship evolved because it was mutualistic. The mitochondria gained a stable environment and safety while the eukaryote gained an abundance of energy. All mutualistic and symbiotic relationships must be thought of in terms of the benefit vs the cost to BOTH organisms

Human homosexual behavior on the surface appears to be unnatural and mal-adaptive. What adaptive benefits might homosexual behavior have in other species? Is there evidence for a genetic component to homosexuality in humans? Why has homosexuality not been under much negative selection in past generations? What experimental evidence suggests a potential genetic benefit to maintaining a "gay" gene in a population?

Social benefits: dominance, friendships

reproductive benefits: practice with mating and parenting behavior

There is a large genetic component in homosexual behavior that appears to be greater in men and in butch women

Gays have tended to engage in reproduction (no negative NS) AND there has been evidence to support that the low RS of a gay male is balanced by high fecundity of female relatives